Rex Tillerson should face questions in a climate lawsuit brought by 21 young people, a federal judge has ruled.

If – as expected – he is confirmed as secretary of state, Tillerson is on the hook to give testimony in what is shaping up to be a seminal court case.

Lawyers for the youth want to quiz the former Exxon Mobil boss on what he knew when about climate science. That will feed into an argument that fossil-friendly feds violated the younger generation’s constitutional rights, in allowing dangerous levels of climate change.

“We believe that Mr Tillerson’s deposition will be extremely important to this case,” said counsel Philip Gregory in a statement.

“The ties between the fossil fuel industry in the federal government run very deep and Mr Tillerson will have much to add on this crucial issue.”

Judge Thomas Coffin said the case will go to trial in summer or autumn 2017, in Eugene, Oregon.

Monday >> Myron Ebell, who headed Trump’s Environmental Protection Agency transition team, is in London talking at an event organised by the Global Warming Policy Foundation. We’ll have it covered.

State visits

The first foreign head of government to visit the White House, Theresa May was preoccupied with securing a post-Brexit trade deal.

In a speech that was swiftly eclipsed by the drama of Donald Trump’s Muslim ban – something he meant literally, it turns out – she did slide in a mention of climate change.

May told Republican senators: “We know that so many of the threats we face today – global terrorism, climate change, organized crime, unprecedented mass movements of people – do not respect national borders. So we must turn towards those multinational institutions like the UN and NATO that encourage international cooperation and partnership.”

The royal family has extended a return invitation to Trump, which could get awkward if Prince Charles wants to talk about his latest project – a Ladybird book on climate change.